1. Field of the Invention
The present invention relates to a printed circuit substrate. More particularly, the present invention relates to an embedded printed circuit substrate having passive parts embedded therein.
2. Description of the Related Art
An embedded printed circuit substrate has passive parts, such as capacitors, embedded therein so that wiring with active parts have short lengths. By constructing a printed circuit substrate in this matter, a more stable print circuit with an acceptable amount of reliability and predetermined electric characteristics is achieved.
Furthermore, a conventional embedded printed circuit substrate can be constructed by employing a substrate having an area smaller than an area of an external printed circuit substrate. Therefore, the embedded printed circuit substrate has become increasingly popular and is employed in many various types of portable electric devices, particularly those in which a minimal size is desired. The above-described embedded printed circuit substrate typically is comprised of active parts, such as semiconductor dies, as well as the passive parts mounted therein, and the embedded printed circuit substrate is also employed in an antennas, etc.
However, a conventional embedded printed circuit substrate, in which the active parts (such as the semiconductor dies) are mounted, has a problem with thermal stability. Furthermore, in the conventional embedded printed circuit substrate, the active parts generating a large amount of heat, such as the semiconductor dies, are buried in an insulating layer, thereby causing a problem in relation to heat radiation, as it is difficult to transfer heat to the exterior of the printed circuit, let alone transfer heat to, for example, a heat sink, etc.
Such problems associated with heat radiation is often responsible for causing erroneous operation of the semiconductor dies. Therefore, with conventional printed circuits substrate having embedding of passive parts, it is often difficult to secure a stable operation characteristic, and the lifetime of such semiconductor dies can be reduced.